Optical signal transfer is becoming more prevalent in computer systems and network communications. Optical signals can propagate in a variety of different media, such as optical fibers and optical waveguides, between different computer systems and network devices. Optical signals that propagate between different propagation media may pass through an optical coupling system. As an example, an optical coupling system can couple an optical fiber with an optical waveguide, such as via a grating. Therefore, the optical signal can propagate between the optical fiber and the optical waveguide. Such optical coupling can result in a loss of optical energy of the optical signal.